In this article, the flux reversal permanent magnet (FRPM) machine with toroidal windings is presented and analyzed with reference to conventional concentrated windings. First, the influence of rotor pole numbers on FRPM machines with conventional concentrated windings is investigated. It is found that although the 12/13 stator slot/rotor pole FRPM machine has a high back electromotive force, the pitch factor, and magnet flux utilization ratio of concentrated windings are very low. By adopting toroidal windings instead of concentrated windings in the 12/13 FRPM machine, the pitch factor and resulted machine performance can be effectively improved. Finite-element analysis shows that the 12/13 FRPM machine with toroidal windings can produce 79% higher torque than its counterpart with concentrated windings. Then, the critical design parameters and detailed electromagnetic performance of FRPM machines with both winding types are analyzed and compared. It is shown that the machine with toroidal windings has higher torque, efficiency, power factor, and lower torque ripple, making it particularly suitable for low-speed, high-torque, and axial length limited applications. In addition, other feasible stator slot/rotor pole combinations to use toroidal winding are identified, with the aid of equivalent pole-pair number. Finally, two 12/13 FRPM prototypes with toroidal windings and concentrated windings are tested to validate the analyses.

中文翻译：

---

环形绕组和集中绕组磁通反向永磁电机的比较分析

在本文中，参考传统的集中绕组，介绍并分析了具有环形绕组的反向磁通永磁 (FRPM) 电机。首先，研究了转子极数对具有传统集中绕组的 FRPM 电机的影响。研究发现，虽然12/13定子槽/转子极FRPM电机具有较高的反电动势，但集中绕组的节距因数和磁通利用率很低。通过在12/13 FRPM电机中采用环形绕组代替集中绕组，可以有效提高节距因数和最终的机器性能。有限元分析表明，具有环形绕组的 12/13 FRPM 电机可以产生比具有集中绕组的对应电机高 79% 的扭矩。然后，分析和比较了两种绕组类型的 FRPM 电机的关键设计参数和详细的电磁性能。结果表明，具有环形绕组的电机具有更高的转矩、效率、功率因数和更低的转矩脉动，使其特别适用于低速、高转矩和轴向长度受限的应用。此外，在等效极对数的帮助下，确定了使用环形绕组的其他可行的定子槽/转子极组合。最后，测试了两个具有环形绕组和集中绕组的 12/13 FRPM 原型以验证分析。使其特别适用于低速、高扭矩和轴向长度有限的应用。此外，在等效极对数的帮助下，确定了使用环形绕组的其他可行的定子槽/转子极组合。最后，测试了两个具有环形绕组和集中绕组的 12/13 FRPM 原型以验证分析。使其特别适用于低速、高扭矩和轴向长度有限的应用。此外，在等效极对数的帮助下，确定了使用环形绕组的其他可行的定子槽/转子极组合。最后，测试了两个具有环形绕组和集中绕组的 12/13 FRPM 原型以验证分析。